This has been bugging me for a long time now. In all the plans and elevations of the Fukushima plants the back-up diesel pumps are not shown. We were simply told again and again that they were “knocked out” or “flooded” by the tsunami. Where were they and what was their failure all about?
I read recently that someone who tests backup diesel generators said many of them fail when tested, and many times the periodic tests to make sure they work are not demanding tests – they are turned on briefly and not subjected to serious stress. When needed, they can fail. Unreliability is not uncommon among all backup generators, and may have little to do with nuclear power, tsunamis, or flooding.
They were in the basement, behind a 20 foot seawall, from what I heard on the news. Apparently the wave was 23 feet.
the electrical systems for the generators to supply the reactor systems was in the basements and damaged to be nonfunctional. the generators were damaged beyond repair.
Where I work, all the building have had emergency generators installed. They are tested every month. As mentioned above, when they are just turned on they work. When the building is actually switched over, they tend not to work. One of the larger buildings has it’s own generator house and UPS. Multiple diesel generators etc. That now works-but it took them literally 2 years of testing and rebuilding to get it functional. All of this was done in response to Katrina. So the planning and installations have taken 5 years. Apparently the idea of switching an entire installation over to local power is much more complicated than it sounds. How well such a system would work after an earthquake or tsunami-well I wouldn’t count on it at all. No matter how well built.
All they had to do is run some pumps…
IIRC, WTC7 had big diesel generators installed for electrical backup, halfway up the building. Plus large tanks of fuel. The only way that was a danger to the building was if massive chunks of flaming debris got quite a way inside the building. What were the odds of that?
These pumps are a bit more considerable than the one that inflates your air mattress.
That said it doesn’t matter how minor the power required is when all of your power generating equipment is under water.
I also saw somewhere (can’t recall where, so no cite) that the tanks for the diesel fuel floated out to sea as the tsunami receded. So there was no fuel to power the generators as well.
I thought the diesel generators were located just seaward of the reactors they respectively powered/were supposed to power.
Here’s a picture of the generator buildings, to the right of the reactor units. Ignore the accompanying story. I didn’t bother reading it.
I believe those buildings to the right in that picture housed the actual generators that were powered by the heat from the nuclear reactors; i.e., the actual generators that produced the electric power from this plant.
Thus not the same as the ‘diesel-powered generators’ that were one of the emergency backups for this plant. Where those were located is not clear; might have been in the same buildings, or might have been elsewhere.
The generators were located in a low area (cannot verify that it was the basement or not).
I just read an article which quoted a member of the Japan nuclear energy safely committee, who said that he had been concerned about tsunami, but his concerns had been brushed aside. The other members were more concerned about damage from earthquake than from tsunami.
The switching to emergency power is not complicated at all. It is just a matter of opening one relay and closing another. What happens is the power on the emergency circuits goes off and then back on. On a building with an elevator bank all the elevators stop. And depending on the system one or two elevators will restart. ON some buildings then the elevators have to be brought to the ground floor the people let out, then switch to the next elevator do the same. After all elevators are empty (no traped people) one or two elevators are left in the auto operation. Other buildings this is done automatically one elevator at a time.
Greg Palast on Emergency Generators:
I don’t see evil in the generators failing (they were flooded out by unprecedentedly high waves, although you’d think there’d be more forethought about tsunamis in a country that occasionally suffers from them). As posters above have noted, emergency generators, even those tested on a regular basis, frequently fail. There’s a difference between a quick test and running for an extended period with a load on the output. It’s just that people don’t seem to really expect to have to use the emergency system a lot of the time. And if they do, not for long.
I can’t think of a better argument than this against nuclear power.
If the emergency generator failed in one of my buildings I would worry about loosing my job.
They should be run weekly and run under load.